Polymeric treatment compositions

ABSTRACT

Polymeric compositions are described comprising a biocompatible polymer including a biodegradable linkage to a visualization agent and a non-physiological solution; wherein the biocompatible polymer is soluble in the non-physiological solution and insoluble in a physiological solution. Methods of forming the solutions and polymers are disclosed as well as methods of therapeutic use.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.15/491,864, filed Apr. 19, 2017, now U.S. Pat. No. 10,258,716, which isa continuation of U.S. patent application Ser. No. 14/736,145, filedJun. 10, 2015, now U.S. Pat. No. 9,655,989, which is a continuation ofU.S. patent application Ser. No. 14/054,515, filed Oct. 15, 2013, nowU.S. Pat. No. 9,078,950, which claims the benefit of U.S. provisionalpatent application No. 61/714,102, filed Oct. 15, 2012, the entiredisclosures each of which are incorporated herein by reference.

FIELD

The present invention relates generally to vascular treatmentcompositions and methods of using these compositions to treat vascularconditions. The compositions can comprise a polymer(s) that transitionsfrom a liquid to a solid upon being subject to physiological conditions.

BACKGROUND

Embolization is widely used to treat vascular malformations, such asaneurysms, arteriovenous malformations, fistulas, and tumors. Thesemalformations can be treated with a variety of different products,including metallic coils, polymer-metal hybrid coils, microparticles,and foams. However, there remains a need for products that can minimizerisks associated with embolization.

SUMMARY

Polymeric compositions are described which comprise: a biocompatiblepolymer including a biodegradable linkage to a visualization agent, anda non-physiological solution; wherein the biocompatible polymer issoluble in the non-physiological solution and insoluble at physiologicalconditions.

Polymeric compositions are described which comprise: a biocompatiblepolymer including a biodegradable linkage to a visualization agent, anda water-miscible organic solvent; wherein the biocompatible polymer issoluble in the organic solvent and insoluble at physiologicalconditions.

Methods are also described for use of the polymeric compositions. In oneembodiment, methods are described comprising injecting through adelivery device into a physiological environment a liquid emboliccomposition comprising: a biocompatible polymer including abiodegradable linkage to a visualization agent, and a non-physiologicalsolution, wherein the biocompatible polymer precipitates when it reachesthe physiological conditions.

In one embodiment, methods are described comprising injecting through adelivery device into a vessel with physiological environment a liquidembolic composition comprising: a biocompatible polymer including abiodegradable linkage to a visualization agent, and a water-miscibleorganic solvent, wherein the biocompatible polymer precipitates when itreaches the physiological conditions and treats the vascular disorder.

The biodegradable linkage can be cleaved by hydrolysis and/or enzymaticcleavage. Biodegradable linkages susceptible to enzymatic cleavage canbe esters or amino acids such as Seq. ID 1, Seq. ID 2, Seq. ID 3, Seq.ID 4, Seq. ID 5, Seq. ID 6, Seq. ID 7, Seq. ID 8, Seq. ID 9, Seq. ID 10,Seq. ID 11, or Seq. ID 12. Biodegradable linkages susceptible tohydrolysis can be an ester, a carbonate, or a polyester.

The biodegradable linked contrast/visualization agent can be aniodinated compound.

The biocompatible polymer can be a reaction product of two or moredifferent monomers and can have a concentration of about 1% w/w to about50% w/w.

The non-physiological solution can be aqueous and can have a pH of lessthan about 5 or a pH of greater than about 8.

In one embodiment, a composition for filling a vascular defect isdescribed comprising: an aqueous solution at non-physiological pH; abiocompatible polymer including a pH sensitive component and abiodegradable linkage to a visualization agent at a concentration offrom about 1% to 50% w/w, that is soluble in the aqueous solution atnon-physiological pH and insoluble at physiological conditions.

In another embodiment, methods are described comprising: providing aliquid embolic composition comprising a biocompatible polymer includinga biodegradable linkage to a visualization agent, and anon-physiological pH aqueous solution, wherein the biocompatible polymeris soluble in the non-physiological pH aqueous solution and insoluble inat physiological conditions; inserting a delivery device into a vessel;guiding the delivery device to an area in need of treatment wherein thearea has physiological conditions; injecting the liquid embolic polymercomposition through the delivery device into the vessel at the area inneed of treatment thereby immediately precipitating the polymer andforming a solid polymeric mass; and treating the vascular condition.

In one embodiment, a composition for filling a vascular defect isdescribed comprising: a water-miscible organic solvent; a biocompatiblepolymer at a concentration of from about 1% to 50% w/w including abiodegradable linkage to a visualization agent, which is soluble in theorganic solvent and insoluble at physiological conditions.

In another embodiment, methods are described comprising: providing aliquid embolic composition comprising a biocompatible polymer includinga biodegradable linkage to a visualization agent, and a water-miscibleorganic solvent, wherein the biocompatible polymer is soluble in theorganic solvent and insoluble in at physiological conditions; insertinga delivery device into a vessel; guiding the delivery device to an areain need of treatment; injecting the liquid embolic polymer compositionthrough the delivery device into the vessel at the area in need oftreatment thereby immediately precipitating the polymer and forming asolid polymeric mass; and treating the vascular condition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a pre-treatment angiogram of a rabbit kidney beforeuse of an embodiment of an embolic polymer.

FIG. 2 illustrates a post-treatment angiogram of a rabbit kidney afteruse of an embodiment of an embolic polymer.

FIG. 3 illustrates a post-treatment CT scan of a rabbit kidney after useof an embodiment of an embolic polymer.

FIG. 4 illustrates a post-treatment angiogram of a rabbit kidney afteruse of an embodiment of an embolic polymer.

FIG. 5 illustrates a post-treatment MR scan of a rabbit kidney after useof an embodiment of an embolic polymer.

DETAILED DESCRIPTION

Described herein generally are polymeric treatment compositionscomprising a biocompatible polymer including a visualization speciescoupled to the polymer by a biodegradable linkage, wherein thebiocompatible polymer can be soluble in selected solvent systems andinsoluble at physiological conditions or in a physiologicalsolution/fluid in a selected solvent. In some embodiments, thevisualization species can be an opacification agent(s) that can permitvisualization in vivo. In other embodiments, the solution can include amiscible solvent that can dissolve the polymer. In other embodiments,the solution can include a non-physiological pH solvent. Thesecompositions can be introduced through a delivery device in the liquidstate and transition to the solid state once in contact with aphysiological fluid.

When a polymer is soluble in solution, it can be easy to deploy througha delivery device, e.g. microcatheter, to a delivery site and/ortreatment site. However, once precipitated out of solution, a polymercan be much more difficult to deploy. For example, once precipitated, apolymer can in some instances be more difficult to deploy through adelivery device. As such, the compositions and methods described hereincan provide polymer treatment solutions to sites that would otherwisenot be easily administered to without being soluble prior to exiting adelivery device.

The compositions can comprise a solution at a non-physiologicalcondition (e.g. non-physiological pH). The solution can include apolymer soluble in the solution but insoluble at physiologicalconditions; the polymer can include a visualization agent biodegradablyattached to it. In some embodiments, the solution can include a polymersoluble in a non-physiological pH aqueous solution but insoluble atphysiological conditions. In another embodiment, the polymer can besoluble in a water-miscible organic solvent but insoluble atphysiological conditions (e.g. water).

A function of the biocompatible polymer, e.g. liquid embolic polymer,can be to precipitate when coming in contact with blood or otherphysiological fluid. If the pH of the physiological fluid is thesolubility trigger, the physiological pH can be a pH of about 7.0, about7.1, about 7.2, about 7.3, about 7.4, about 7.5, about 7.6, about 7.7 orabout 7.8, between about 7.0 and about 7.8, between about 7.1 and about7.7, between about 7.2 and about 7.6, or any value in a range bound byor between any of these values. The non-physiological pH can be a pHbetween about 1.0 and about 6.9, or about 2.0 and about 6.0, about 7.9and about 12.0, about 8.5 and about 10.0. Alternatively, if thesolubility trigger is solubility in a water miscible organic solvent andinsolubility at physiological conditions, any physiological environmentcan initiate the precipitation.

Precipitation of the polymer at physiological conditions can be used toocclude a biological structure. Control of the liquid embolic polymer'ssolubility can be achieved by selection of the composition of thepolymer. The polymer can be prepared with monomers having ionizablemoieties. In some embodiments, the polymers can be a reaction product oftwo different monomers, three different monomers, four differentmonomers, five different monomers, or more. In the case of a pHsensitive solubility trigger, a hydrophobic polymer can be constructedwith a minimum amount of ionizable moieties to render the polymersoluble in non-physiological pH solutions. The ratio of monomers withionizable moieties and other monomers can be dependent on the structureof the monomers and can be determined experimentally.

Polymers sensitive to pH such as amino-containing liquid embolicpolymers can be dissolved in a low pH solution, the amines may besubstantially protonated and can enhance the solubility of the polymer.The resulting solution can be placed in conditions with physiological pHand the amines can deprotonate and render the polymer insoluble.Conversely, carboxylic acid-containing polymers can be dissolved in ahigh pH solution, the carboxylic acids can be substantially deprotonatedand enhance the solubility of the polymer. The resulting solution can beplaced in conditions with physiological pH and the carboxylic acids canprotonate and render the polymer insoluble.

A monomer or monomers can include at least one visualization specieslinked to the monomer to impart visibility of the liquid embolic polymerwhen imaged using a medically relevant imaging technique such asfluoroscopy, computed tomography, or magnetic resonance techniques.Characteristic features of the monomers with visualization species canbe cores that are visible under medically relevant imaging techniquesand a polymerizable moiety attached to the core with a biodegradablelinkage.

A visualization agent can also be linked after polymerization if areactive pendent group is added to the polymerization mixture beforepolymerization. An exemplary reactive pendent group can be an acrylatemonomer having an epoxide pendent group (e.g., glycidyl acetate) or ahydroxyl ethyl pendent group. A skilled artisan can envision otherpendent groups that can be added to a formed polymer.

Visualization of the polymer under fluoroscopy and CT imaging can beimparted by the use of monomers with cores containing iodine,particularly aromatic rings with a plurality of iodine atoms. A corecontaining iodine can be triiodophenol. Concentrations of iodine torender the liquid embolic visible using fluoroscopy or CT imaging canrange from about 10% to about 60% w/w, about 20% to about 50% w/w, orabout 30% to about 40% w/w of the liquid embolic solution. Visualizationof the polymer under magnetic resonance imaging can be imparted by theincorporation of monomers containing gadolinium. A visualization agentfor magnetic resonance imaging can be gadoliniumdiethylenetriaminepentaacetic acid aminoethylmethacrylate.Concentrations of gadolinium to render the liquid embolic visible usingmagnetic resonance imaging can range from about 0.1% to about 1% w/w,about 0.5% to about 1% w/w, or about 0.1% to about 0.5% w/w of theliquid embolic solution.

Some monomers can contain a polymerizable moiety and optionally anionizable moiety. Polymerizable moieties can be those that permit freeradical or anionic polymerization, including but not limited toacrylates, methacrylates, acrylamides, methacrylamides, vinyl groups,and derivatives thereof. Alternatively, other reactive chemistries canbe employed to polymerize the liquid embolic polymer, such as, but notlimited to nucleophile/N-hydroxysuccinimde esters, nucleophile/halide,vinyl sulfone/acrylate or maleimide/acrylate. Preferred polymerizablemoieties can be acrylates and acrylamides.

Other monomers can contain a polymerizable moiety and can have astructure that is conducive to desired solubility characteristics.Polymerizable moities can be those that permit free radicalpolymerization, including but not limited to acrylates, methacrylates,acrylamides, methacrylamides, vinyl groups, and derivatives thereof.Alternatively, other reactive chemistries can be employed to polymerizethe liquid embolic polymer, i.e. nucleophile/N-hydroxysuccinimde esters,nucleophile/halide, vinyl sulfone/acrylate or maleimide/acrylate.Preferred polymerizable moieties can be acrylates and acrylamides. Ingeneral, other monomers can compensate for monomers includingvisualization species.

If a polymer is too hydrophobic for dissolution in a water misciblesolvent, more hydrophilic monomers can be introduced to alter thesolubility. If a polymer is too hydrophilic and is soluble in water,more hydrophobic monomers can be introduced to alter the solubility.Other monomers can include hydroxyethyl methacrylate, t-butyl acrylate,t-butyl acrylamide, n-octyl methacrylate, and methyl methacrylate. Suchmonomers can be present at a concentration of about 1% w/w to about 50%w/w, about 1% w/w to about 40% w/w, about 1% w/w to about 30% w/w, about1% w/w to about 20% w/w, about 1% w/w to about 15% w/w, about 1% w/w toabout 10% w/w, about 2% w/w to about 15% w/w, about 2% w/w to about 20%w/w, about 2% w/w to about 10% w/w, about 1% w/w, about 2% w/w, about 3%w/w, about 4% w/w, about 5% w/w, about 6%, about 7% w/w, about 8%, about9% w/w, about 10% w/w, about 11% w/w, about 12% w/w, about 13% w/w,about 14% w/w, about 15% w/w, about 16% w/w, about 17% w/w, about 18%w/w, about 19% w/w, about 20% w/w, about 21% w/w, about 22% w/w, about23% w/w, about 24% w/w, or about 25% w/w.

Some monomers can include biodegradable linkages to visualizationspecies. Biodegradable linkages can permit separation of thevisualization core from the polymer. After separating from the polymer,the core can be removed by diffusion and/or by cells comprising theforeign body response to the polymer. Biodegradable linkages can beseparated into two types. The two types can include those susceptible tohydrolysis and those susceptible to enzymatic action. Linkagessusceptible to hydroylsis can generally include esters, polyesters, orcarbonates.

The biodegradable linkages can be introduced into monomers or thepolymers after formation. One skilled in the art can envision benefitsto both methods of introducing biodegradable linkages into the polymers.

Ester linkages can be introduced by reacting hydroxyl groups with cyclicanhydrides, such as succinic or glutaric anhydride, or cylic esters,such as lactide, glycolide, ε-caprolactone, and trimethylene carbonate.The rate of degradation can be controlled by ester selection and thenumber of esters inserted into biodegradable linkages.

Linkages susceptible to enzymatic action can include peptides that canbe degraded by enzymes, such as but not limited to matrixmetalloproteinases, collagenases, elastases, cathepsin, or a combinationthereof. Peptide sequences degraded by matrix metalloproteinases caninclude Gly-Pro-Gln-Gly-Ile-Ala-Ser-Gln (Seq. ID 1),Gly-Pro-Gln-Pro-Ala-Gly-Gln (Seq. ID 2), Gly-Pro-Gln-Gly-Ala-Gly-Gln(Seq. ID 3), Lys-Pro-Leu-Gly-Leu-Lys-Ala-Arg-Lys (Seq. ID 4),Gly-Pro-Gln-Ile-Trp-Gly-Gln (Seq. ID 5), and Gln-Pro-Gln-Gly-Leu-Ala-Lys(Seq. ID 6). Peptide sequences degraded by cathepsin can includeGly-Phe-Gln-Gly-Val-Gln-Phe-Ala-Gly-Phe (Seq. ID 7),Gly-Phe-Gly-Ser-Val-Gln-Phe-Ala-Gly-Phe (Seq. ID 8), andGly-Phe-Gly-Ser-Thr-Phe-Phe-Ala-Gly-Phe (Seq. ID 9). Peptide sequencesdegraded by collagenase can include Gly-Gly-Leu-Gly-Pro-Ala-Gly-Gly-Lysand Ala-Pro-Gly-Leu (Seq. ID 10). Peptide sequences degraded by papaincan include Gly-Phe-Leu-Gly (Seq. ID 11). Peptide sequences degraded bycaspase-3 can include Asp-Glu-Val-Asp-Thr (Seq. ID 12). The rate ofdegradation can be controlled by the peptide sequence selection.

In one embodiment, liquid embolic polymers can be polymerized fromsolutions of monomers linked to visualization species and optionallyother monomers, or from solutions of monomers whose later polymers arelinked to visualization species. The solvent used to dissolve themonomers can be any solvent that dissolves the desired monomers.Solvents can include methanol, acetonitrile, dimethyl formamide, anddimethyl sulfoxide.

Polymerization initiators can be used to start the polymerization of themonomers. The polymerization can be initiated by reduction-oxidation,radiation, heat, or any other method known in the art. Radiationcross-linking of the monomer solution can be achieved with ultravioletlight or visible light with suitable initiators or ionizing radiation(e.g. electron beam or gamma ray) without initiators. Polymerization canbe achieved by application of heat, either by conventionally heating thesolution using a heat source such as a heating well, or by applicationof infrared light to the monomer solution.

In one embodiment, the polymerization initiator can beazobisisobutyronitrile (AIBN) or a water soluble AIBN derivative(2,2′-azobis(2-methylpropionamidine) dihydrochloride). Other initiatorscan include N,N,N′,N′-tetramethylethylenediamine, ammonium persulfate,benzoyl peroxides, azobisisobutyronitriles and combinations thereof.Initiator concentrations can be from about 0.1% w/w to about 5% w/w,about 0.5% w/w to about 3% w/w, about 0.25% w/w, about 0.5% w/w, about0.75% w/w, about 1% w/w, about 1.25% w/w, about 1.50% w/w, about 1.75%w/w, or about 2% w/w, about 3%, about 4%, or about 5% of the mass of themonomers in solution, or any range or value within the listedpercentages. The polymerization reaction can be performed at elevatedtemperatures, of about 30° C. to about 200° C., about 50° C. to about100° C., about 50° C., about 60° C., about 70° C., about 80° C., about90° C. or about 100° C. or can proceed at room temperature withoutheating. After the polymerization is completed, the polymer can berecovered by precipitation in a non-solvent and dried under vacuum.

A water-miscible organic solvent can dissolve the final liquid embolicpolymer. Concentrations of the polymer in an organic solvent can be fromabout 1% to about 50%, about 2.5% to about 25%, about 5% to about 15%,about 2.5%, about 5%, about 7.5%, about 10%, about 12.5%, about 15%,about 17.5%, about 20%, about 22.5%, about 25%, about 30%, about 35%,about 40%, about 45%, or about 50%, or any percentage or range ofpercentages bound by the above percentages. Solvents can includemethanol, acetonitrile, dimethyl formamide, dimethyl isosorbide, anddimethyl sulfoxide.

Also, if a pH sensitive monomer is used within the polymer, anon-physiological pH aqueous solution can dissolve the liquid embolicpolymer. Polymer concentrations in an aqueous solution can be from about1% to about 50%, about 2.5% to about 25%, about 5% to about 15%, about2.5%, about 5%, about 7.5%, about 10%, about 12.5%, about 15%, about17.5%, about 20%, about 22.5%, about 25%, about 30%, about 35%, about40%, about 45%, or about 50%, or any percentage or range of percentagesbound by the above percentages. The aqueous solution can contain aminimum amount of buffer to maintain a non-physiologic pH afterdissolution of the liquid embolic polymer, but not adversely affect thepH of the patient after administration. Alternatively, a buffer may notbe needed. Buffer concentrations can range from about 1 mM to about 100mM, about 20 mM to about 80 mM, about 30 mM to about 70 mM, about 40 mMto about 60 mM, about 45 mM to about 55 mM, about 10 mM, about 20 mM,about 30 mM, about 40 mM, about 50 mM, about 60 mM, about 70 mM, about80 mM, about 90 mM, about 100 mM or any concentration or range ofconcentrations within the values listed.

For liquid embolic polymers containing amines, buffers can includecitrate and acetate and solution pHs can be from about 3 to about 6,from about 3 to about 5, about 3, about 4, about 5 or about 6. Forliquid embolic polymers containing carboxylic acids, buffers can includecarbonate, N-cyclohexyl-2-aminoethanesulfonic acid (CHES),N-cyclohexyl-2-hydroxyl-3-aminopropanesulfonic acid (CAMPSO),N-cyclohexyl-3-aminopropanesulfonic acid (CAPS),3-[4-(2-Hydroxyethyl)-1-piperazinyl]propanesulfonic acid (HEPPS orEPPS), 3-(N-morpholino)propanesulfonic acid (MOPS),4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES),2-(N-morpholino)ethanesulfonic acid (MES) and2-amino-2-methyl-1-propanol (AMP) and solution pH's can be from about 8to about 11, from about 8 to about 10, about 8, about 9, about 10 orabout 11.

The liquid embolic polymers, solutions, and mixtures described hereincan be sterilized without substantially degrading the polymer. Aftersterilization, at least about 50%, about 60%, about 70%, about 80%,about 90%, about 95% about 99% or about 100% of the polymer can remainintact. In one embodiment, sterilization can be by autoclaving and canbe utilized before administration of the polymer.

The liquid embolic polymer formulation can be removed from a vial usinga needle and syringe, and the syringe can be later connected to adelivery device or catheter. Alternatively, the liquid embolic polymerformulation can be prepackaged in a delivery syringe.

To prevent premature liquid embolic polymer deposition, a deliverydevice or catheter can be primed with a bolus of the same flushingsolution or similar water-miscible organic solvent and/ornon-physiological pH aqueous solution as used to dissolve the liquidembolic polymer. This flushing can prevent clogging of the deliverycatheter with the liquid embolic polymer. The syringe containing theliquid embolic formulation can then be connected to the proximal end ofa delivery catheter, such as a microcatheter, cannula, or the like, andpositioned in the desired anatomical site.

As the liquid embolic formulation is injected, it can push the solventflushing solution out of the microcatheter. The solubility of the liquidembolic polymer can then rapidly change as it is exposed tophysiological conditions. The progress of the liquid embolic formulationinside the delivery catheter can be observed using an imaging techniquecompatible with the covalently linked visualization agent or agentsselected. With continued injection, the liquid embolic formulation canenter a target delivery site as a solid mass.

The aqueous nature of physiological conditions can reduce the solubilityof the liquid embolic polymer and cause it to precipitate from thewater-miscible, organic solvent. Alternatively or in addition to theaqueous nature of the physiological conditions, the large bufferingcapacity of the body's tissues can cause pH of the fluids to changerapidly thus reducing the solubility of the liquid embolic polymer andcausing it to precipitate from solution. The precipitated liquid embolicpolymer can provide occlusion of a target site.

Over time, the biodegradable linkages binding the visualization agentsto the liquid embolic polymer can be broken and the visualization of theliquid embolic polymer can be diminished. In some embodiments, about40%, about 50%, about 60%, about 70% about 80%, about 90%, about 95%,about 99% or about 100% of the biodegradably linked visualization agentscan remain intact after about 5 days, about 2 weeks, about 1 month,about 2 months, about 6 months, about 9 months, about a year, about 2years, about 5 years, about 10 years or about 20 years. Polymers can befine tuned to degrade faster or slower.

The precipitated, solidified liquid embolic polymer can providelong-term occlusion of the target site. The precipitated liquid embolicpolymer can remain substantially stable once implanted. For example, theliquid embolic polymer can remain greater than 60%, 70% 80%, 90%, 95%,or 99%, or nearly 100% intact after at least about 5 days, about 2weeks, about 1 month, about 2 months, about 6 months, about 9 months,about a year, about 2 years, about 5 years, about 10 years or about 20years.

In some embodiments, it may be desirable for the entire precipitatedliquid embolic polymer to degrade over time. In such embodiments, theliquid embolic polymer can degrade to less than 40%, 30% 20%, 10%, 5% or1% intact after at least about 5 days, about 2 weeks, about 1 month,about 2 months, about 6 months, about 9 months, about a year, about 2years or about 5 years.

Further, the liquid embolic polymers once precipitated can be cohesiveenough to stick to the tissue and/or remain in place through frictionwith the tissues and forces of circulating blood. In other embodiments,the precipitated polymer can act as a plug in a vessel held in place bythe flow and pressure of the blood.

In one embodiment described herein, the liquid embolic polymer comprisesa reaction product of2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethylacrylate, hydroxyethyl methacrylate, and azobisisobutyronitrile. Inanother embodiment, the liquid embolic polymer comprises a reactionproduct of between about 75% and about 98%2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethylacrylate, between about 2% and about 25% hydroxyethyl methacrylate, andless than about 1% azobisisobutyronitrile. In still another embodiment,the liquid embolic polymer comprises a reaction product of between about85% and about 98%2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-yloxy)ethoxy)ethylacrylate, between about 2% and about 15% hydroxyethyl methacrylate, andless than about 1% azobisisobutyronitrile.

In another embodiment described herein, the liquid embolic polymercomprises a reaction product of1-((2-(methacryloyloxy)ethoxy)carbonyloxy) ethyl3,5-diacetamido-2,4,6-triiodobenzoate, hydroxyethyl methacrylate, andazobisisobutyronitrile. In another embodiment, the liquid embolicpolymer comprises a reaction product of between about 85% and about 98%1-((2-(methacryloyloxy)ethoxy)carbonyloxy) ethyl3,5-diacetamido-2,4,6-triiodobenzoate, between about 2% and about 15%hydroxyethyl methacrylate, and less than about 1%azobisisobutyronitrile.

In still another embodiment described herein, the liquid embolic polymercomprises a reaction product of1-((2-(methacryloyloxy)ethoxy)carbonyloxy) ethyl3,5-diacetamido-2,4,6-triiodobenzoate, N-(3-Aminopropyl)methacrylamidehydrochloride, and azobisisobutyronitrile. In another embodiment, theliquid embolic polymer comprises a reaction product of about 74%1-((2-(methacryloyloxy)ethoxy)carbonyloxy) ethyl3,5-diacetamido-2,4,6-triiodobenzoate, about 26%N-(3-Aminopropyl)methacrylamide hydrochloride, and less than about 1%azobisisobutyronitrile.

Example 1 Preparation of an Iodine-Containing Monomer

A. To 250 mL of toluene, 15 g 2,4,6-triiodophenol, 22.9 g3,6-dimethyl-1,4dioxane-2,5 dione, and 25 μL of stannous octoate wereadded. The solution was refluxed for 18 hr. After cooling the solutionto 25° C., 3 mL acryloyl chloride and 5.2 mL triethylamine dissolved in50 mL toluene were added. The mixture was stirred for 5 hr, filtered,washed with water, and dried under vacuum.

B. To 2400 mL of toluene, 120.0 g 2,4,6-triiodophenol, 73.2 g3,6-dimethyl-1,4-dioxane-2,5-dione, 29.4 g glycolide, and 200 μLstannous octoate were added. The solution was refluxed for 24 hours.After cooling the solution to 25° C., 24.8 mL acryloyl chloride and 42.4mL triethylamine were added. The mixture was stirred for 18 hours,filtered, and dried under vacuum.

Example 2 Preparation of an Gadolinium-Containing Monomer

To 50 mL of dimethylformamide, 17.5 g gadolinium diethylene triaminepentaacetic acid, 13 g 3,6-dimethyl-1,4-dioxane-2,5 dione, and 25 μL ofstannous octoate were added. The solution was refluxed for 18 hr. Aftercooling the solution to 10° C., 3 mL acryloyl chloride and 5.2 mLtriethylamine dissolved in 50 mL dimethylformamide were added. Themixture was stirred for 18 hr, filtered, and the solvent was removed.

Example 3 Preparation of Another Iodine-Containing Monomer

To 400 mL of methanol was added 104 g (170 mmol) of diatrizoic acidfollowed by 28 g of cesium carbonate (65 mmol). After stirring for 45min the methanol was removed in vacuo and the solids suspended in 500 mLdiethyl ether. The solids were then collected on a Buchner funnel, driedin vacuo, to yield 120 g, (95%) of cesium diatriozate.

To 24 mL of HEMA (200 mmol) in 1000 mL of dry ether was added 16.8 mL(213 mmol) of pyridine at 4-10° C., under argon. To this solution wasadded 21.3 mL (200 mmol) of 1-chloroethyl chlorocarbonate, drop wisewith stirring over 0.5 hour. After stirring for 0.5 hour at 4-10° C.,the heavy precipitate was removed by filtration and the filtrate wasconcentrated to an oil in vacuo, yielding 44 g (100%) ofHEMA-1-chloroethyl carbonate.

To 44 g (200 mmol) of HEMA-1-chloroethyl carbonate in 400 mL ofanhydrous DMF, was added 30 g (40 mmol) of cesium diatriozate at 100°C., under argon, with good stirring. After 15 minutes another 40 g (54mmol) of cesium diatriozate was added at 100° C., under Ar, with goodstirring followed by a final 30 g (40 mmol), under the same conditions,for a total of 110 g cesium diatriozate (134 mmol). The reddish brownreaction mixture was heated at 100° C. for an additional hour and thesolvent was removed in vacuo. The reddish brown solid residue wassuspended in 1000 mL of dry ether and the solids collected on a Buchnerfunnel. After the solids were dried in vacuo they were suspended in 500mL distilled water at 2000 rpm and the pH of the mixture adjusted to 8-9with cesium carbonate. After stirring for 10 min the suspension wasfiltered and the solids washed 3×100 mL of distilled water, driedovernight in vacuo and crushed to a fine powder. Solid residue was againsuspended in 1000 mL of dry ether and the solids collected on a Buchnerfunnel. After the solids were dried in vacuo again and crushed to a finepowder again they were purified by silica gel chromatography using a 1.5Kg column and a 0-10% gradient of MeOH in dichloromethane, over 1 hour.This yielded 26 g (18%), very pale yellow crystalline solid.

Example 4 Preparation of an Iodine-Containing Polymer

A. To 3 mL of dimethyl sulfoxide, 1.8 g triiodophenol chain extendedwith an average of 5 lactide units and capped with an acrylate, 0.2 g ofhydroxyethyl methacrylate, and 10 mg of azobisisobutyronitrile wereadded. Upon complete dissolution of all components, the solution wasplaced at 80° C. for 4 hr. After cooling to room temperature, thepolymer was recovered by precipitation in ethyl ether and dried undervacuum.

B. To a 10 mL vial was added 3 mL of dimethyl sulfoxide, 1.7 g of iodinemonomer prepared in Example 1B, 0.3 g of hydroxyethyl methacrylate, and10 mg of azobisisobutyronitrile. Upon complete dissolution of allcomponents, the vial was degassed and sparged with argon. The solutionwas then placed in an 80° C. oven for 48 hours to polymerize. Aftercooling to room temperature, the polymer was recovered by precipitationin ethyl ether and dried under vacuum. It was then dissolved in THF,flashed on a silica column, then redissolved in THF. It was thenprecipitated in water and then lyophilized to yield the dry polymerproduct.

Example 5 Preparation of an Iodine-Containing Polymer

To 14 g of dimethylformamide, 8 g of the iodine containing monomerprepared in Example 3, 1.4 g of hydroxyethyl methacrylate and 47 mg ofazobisisobutyronitrile were added. Upon complete dissolution of allcomponents the solution was placed at 80° C. for 48 hr. After cooling toroom temperature, the polymer was recovered by precipitation in ethylether and dried under vacuum.

Example 6 Preparation of an Iodine-Containing Polymer

To 6 g of n-methyl-2-pyrrolidone, 1.7 g of the iodine containing monomerprepared in Example 3, 0.25 g of aminopropylmethacrylamide and 10 mg ofazobisisobutyronitrile were added. Upon complete dissolution of allcomponents the solution was placed at 80° C. for 8 hr. After cooling toroom temperature, the polymer was recovered by precipitation in ethylether and dried under vacuum.

Example 7 Precipitation

Iodine containing polymers were dissolved in their respective solvents,e.g. aqueous soluble polymers were dissolved in pH 3 buffered solutionand organic soluble iodine containing polymers were dissolved indimethyl sulfoxide. The solutions were dispensed into 0.1 M phosphatebuffered saline solution. The precipitate formed was ranked from 1 to 5,with 1 being least cohesive and 5 being most cohesive.

Sample Iodine monomer Solvent Cohesiveness 1 Triiodophenol DMSO 4 2Diatrizoic acid DMSO 4 3 Diatrizoic acid pH 3 buffer 3The examples above show that variations in cohesiveness can be achievedby variations in the formulation.

Example 8 Flow

In a flow model, liquid embolic formulations were delivered through0.017″ I.D. microcatheters. The formulations were assessed visually forcohesiveness, injection pressure, plug formation and precipitationspeed. Precipitation speed was ranked slow, medium and fast. All otherswere ranked 1 to 5 with 1 being least desired and 5 being most desired.

Iodine Precipitation Cohe- Injection Plug Sample Monomer Speed sivenessPressure Formation 1 Triiodophenol Fast 3 5 4 4 Diatrizoic acid Slow 4 45 5 Diatrizoic acid Medium 4 5 4The examples above show that variations in flow properties can beachieved by variations in the formulation.

Example 9 Preparation of Liquid Embolic Formulation

To 9 g of dimethyl sulfoxide, 1 g of the polymer of Example 3 was added.The liquid embolic formulation was then aliquoted into vials and capped.The vials were autoclaved at 121° C. for 15 min.

Example 10 Titration of the Iodine Content of the Polymer

Using the techniques described in Examples 1 and 3, the polymersdescribed in the table were prepared. The iodine content of the polymerswas investigated using an inductively coupled plasma-mass spectroscopytechnique.

Fraction Fraction Iodine t-butyl Example 1 Concentration Polymeracrylate monomer (ug/g) 1 0.55 0.45 186,000 2 0.4 0.6 289,000 3 0.250.75 309,000 4 0.1 0.9 329,500

The results of the above table show how the iodine content of the liquidembolic polymer can be controlled by the amount of iodine containingmonomer used in the preparation of the polymer.

Example 11 In Vivo Evaluation of the Liquid Embolic Device—Rabbit Kidney

The liquid embolic formulation prepared according to the techniques ofExamples 4, 5, and 6 was utilized for the embolization of a rabbitkidney. Angiographic occlusion was obtained in the kidney both beforethe procedure (FIG. 1) and after the procedure (FIG. 2). As illustrated,blood flow to the kidney is substantially depleted and replaced with anembolic polymer in FIG. 2. The vessels in FIG. 2 are visible inangiogram.

Example 12 CT Evaluation of the Liquid Embolic Device

The liquid embolic formulation prepared according to the techniques ofExamples 1, 2, and 3 was utilized for the embolization of the renalvasculature of rabbits. At the end of the procedure, the rabbit wereimaged using a CT scanner. When comparing blood flow to the kidney inFIG. 1 to the vasculature filled with CT visible embolic polymer in FIG.3, it is clear that blood flow in FIG. 1 has been replaced by embolicpolymer in FIG. 3.

Example 13 MR Evaluation of the Liquid Embolic Device

The liquid embolic formulation prepared according to the techniques ofExamples 1, 2, and 3 was utilized for the embolization of the renalvasculature of rabbits. At the end of the procedure, the rabbit wereimaged using a MR scanner. FIG. 4 illustrates an angiogram of the kidneyincluding visible replacement of blood flow with liquid embolic polymervisible under an angiogram. FIG. 5 illustrates the embolic polymervisibility under MR angiography.

Unless otherwise indicated, all numbers expressing quantities ofingredients, properties such as molecular weight, reaction conditions,and so forth used in the specification and claims are to be understoodas being modified in all instances by the term “about.” Accordingly,unless indicated to the contrary, the numerical parameters set forth inthe specification and attached claims are approximations that may varydepending upon the desired properties sought to be obtained by thepresent invention. At the very least, and not as an attempt to limit theapplication of the doctrine of equivalents to the scope of the claims,each numerical parameter should at least be construed in light of thenumber of reported significant digits and by applying ordinary roundingtechniques. Notwithstanding that the numerical ranges and parameterssetting forth the broad scope of the invention are approximations, thenumerical values set forth in the specific examples are reported asprecisely as possible. Any numerical value, however, inherently containscertain errors necessarily resulting from the standard deviation foundin their respective testing measurements.

The terms “a,” “an,” “the” and similar referents used in the context ofdescribing the invention (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or clearly contradicted by context.Recitation of ranges of values herein is merely intended to serve as ashorthand method of referring individually to each separate valuefalling within the range. Unless otherwise indicated herein, eachindividual value is incorporated into the specification as if it wereindividually recited herein. All methods described herein can beperformed in any suitable order unless otherwise indicated herein orotherwise clearly contradicted by context. The use of any and allexamples, or exemplary language (e.g., “such as”) provided herein isintended merely to better illuminate the invention and does not pose alimitation on the scope of the invention otherwise claimed. No languagein the specification should be construed as indicating any non-claimedelement essential to the practice of the invention.

Groupings of alternative elements or embodiments of the inventiondisclosed herein are not to be construed as limitations. Each groupmember may be referred to and claimed individually or in any combinationwith other members of the group or other elements found herein. It isanticipated that one or more members of a group may be included in, ordeleted from, a group for reasons of convenience and/or patentability.When any such inclusion or deletion occurs, the specification is deemedto contain the group as modified thus fulfilling the written descriptionof all Markush groups used in the appended claims.

Certain embodiments are described herein including the best mode knownto the inventors for carrying out the invention. Of course, variationson these described embodiments will become apparent to those of ordinaryskill in the art upon reading the foregoing description. The inventorexpects skilled artisans to employ such variations as appropriate, andthe inventors intend for the invention to be practiced otherwise thanspecifically described herein. Accordingly, this invention includes allmodifications and equivalents of the subject matter recited in theclaims appended hereto as permitted by applicable law. Moreover, anycombination of the above-described elements in all possible variationsthereof is encompassed by the invention unless otherwise indicatedherein or otherwise clearly contradicted by context.

In closing, it is to be understood that the embodiments of the inventiondisclosed herein are illustrative of the principles of the presentinvention. Other modifications that may be employed are within the scopeof the invention. Thus, by way of example, but not of limitation,alternative configurations of the present invention may be utilized inaccordance with the teachings herein. Accordingly, the present inventionis not limited to that precisely as shown and described.

We claim:
 1. An embolic system including: a container including aformulation comprising a substantially stable polymer dissolved in anon-physiological solution, wherein the polymer includes a biodegradablelinkage to a visualization agent wherein the visualization agent isformed from a monomer having at least one aromatic ring and at least onepolymerizable moiety, and wherein the polymer is insoluble in aphysiological solution.
 2. The embolic system of claim 1, wherein thecontainer is a vial or a syringe.
 3. The embolic system of claim 1,wherein the biodegradable linkage is Seq. ID 1, Seq. ID 2, Seq. ID 3,Seq. ID 4, Seq. ID 5, Seq. ID 6, Seq. ID 7, Seq. ID 8, Seq. ID 9, Seq.ID 10, Seq. ID 11, Seq. ID 12, Seq. ID 13, an ester, a polyester, or acombination thereof.
 4. The embolic system of claim 1, wherein themonomer having at least one aromatic ring and at least one polymerizablemoiety is2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-y-loxy)ethoxy)ethyl acrylate.
 5. The embolic system of claim 1 furthercomprising a second monomer including at least one hydroxyl group. 6.The embolic system of claim 5, wherein the monomer is an acrylate. 7.The embolic system of claim 6, wherein the acrylate is hydroxyethylmethacrylate.
 8. The embolic system of claim 1, wherein thenon-physiological solution is a water miscible solvent, dimethylformamide or dimethyl sulfoxide.
 9. The embolic system of claim 1including a reaction product of between about 75% and about 98%2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-y-loxy)ethoxy)ethyl acrylate, between about 2% and about 25% hydroxyethylmethacrylate, and less than 1% azobisisobutyronitrile.
 10. The embolicsystem of claim 1 including a reaction product of between about 85% andabout 98% 1-((2-(methacryloyloxy)ethoxy)carbonyloxy) ethyl3,5-diacetamido-2,4,6-triiodobenzoate, between about 2% and about 15%hydroxyethyl methacrylate, and less than 1% azobisisobutyronitrile. 11.The embolic system of claim 1, wherein substantially stable is where thepolymer is greater than 90% intact after about 1 month after animplantation procedure, where the polymer is greater than 60% intactafter about 1 year after the implantation procedure, where the polymeris greater than 60% intact after about 5 years after the implantationprocedure, where the polymer is greater than 90% intact after about 2months after the implantation procedure, or where the polymer is greaterthan 80% intact after about 6 months after the implantation procedure.12. An embolic system including: a container including a formulation,wherein the formulation includes a substantially stable biocompatiblepolymer comprising a reaction product of: a first monomer including apolymerizable moiety having a biodegradable linkage to a visualizationagent having at least one aromatic ring, wherein the at least onearomatic ring includes a plurality of iodine atoms, and a second monomerincluding a polymerizable moiety and at least one hydroxyl group; and anon-physiological solution; wherein the substantially stablebiocompatible polymer is soluble in the non-physiological solution andinsoluble in a physiological solution.
 13. The embolic system of claim12, wherein the container is a vial or a syringe.
 14. The embolic systemof claim 12, wherein the biodegradable linkage is Seq. ID 1, Seq. ID 2,Seq. ID 3, Seq. ID 4, Seq. ID 5, Seq. ID 6, Seq. ID 7, Seq. ID 8, Seq.ID 9, Seq. ID 10, Seq. ID 11, Seq. ID 12, Seq. ID 13, an ester, apolyester, ora combination thereof.
 15. The embolic system of claim 12,wherein the first monomer including a polymerizable moiety having abiodegradable linkage to a visualization agent having at least onearomatic ring is2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-y-loxy)ethoxy)ethyl acrylate.
 16. The embolic system of claim 12, whereinthe non-physiological solution is a water miscible solvent, dimethylformamide or dimethyl sulfoxide.
 17. The embolic system of claim 12,wherein the non-physiological solution has a pH of less than 5 orgreater than
 8. 18. The embolic system of claim 12, wherein thesubstantially stable biocompatible polymer has a concentration of about1% w/w to about 50% w/w.
 19. The embolic system of claim 12, wherein thereaction product is of between about 75% and about 98%2-oxo-2-(1-oxo-1-(1-oxo-1-(2,4,6-triiodophenoxy)propan-2-yloxy)propan-2-y-loxy)ethoxy)ethyl acrylate, between about 2% and about 25% hydroxyethylmethacrylate, and less than 1% azobisisobutyronitrile.
 20. The embolicsystem of claim 12, wherein the reaction product is of between about 85%and about 98% 1-((2-(methacryloyloxy)ethoxy)carbonyloxy)ethyl3,5-diacetamido-2,4,6-triiodobenzoate, between about 2% and about 15%hydroxyethyl methacrylate, and less than 1% azobisisobutyronitrile.